In wireless communications networks such as Long-Term Evolution (LTE) networks, OFDM transmissions use a 15 kHz spacing between two adjacent subcarriers for most applications. A 7.5 kHz subcarrier spacing was proposed for dedicated evolved Multimedia Broadcast Multicast Service (e-MBMS) service. A given transmitter transmits using one subcarrier spacing or the other. Resource block (RB) channelization involves defining resource blocks as the unit of allocation. In LTE, a respective fixed channelization is defined for each of the 15 kHz and 7.5 kHz options; the channelization for 15 kHz employs 12 subcarriers per resource block, and the channelization for 7.5 kHz employs 24 subcarriers per resource block. The resource blocks for both channelizations have 180 kHz bandwidth (BW).
In LTE, as discussed above, a frame structure is employed that is not flexible, and fixed resource block definitions are used. RB allocation to a user equipment (UE) is performed using an RB allocation indicator bitmap. The size of the RB allocation indicator bitmap is proportional to system bandwidth. In an LTE RB allocation indicator bitmap, ones and zeros indicate which RBs are assigned to a UE, where one means assigned, zero means not assigned. LTE provides for type 0/1/2 RB allocation indicator bitmaps, all of which have a fixed size for a given bandwidth, regardless of how many RBs a UE occupies. The LTE RB allocation approach can be inefficient when different types of traffic co-exist and/or a same bitmap size is used to allocate RBs for all types of traffics within a moderate-to-large bandwidth.